Thread-controlling device for sewing-machines.



No. 78,584. Patented Nov. I8, I902. E. B. ALLEN.

THREAD CONTROLLING DEVICE FOR SEWING MACHINES.

(Application filed Mar. 31, 1902.)

(No Model.) 2 Sheets-Sheet l.

WTNE/EEI I j N0. 7l3,584. Paient ed Nov. I8, 1902.

E. B. ALLEN.

THREAD CONTROLLING DEVICE FOR SEWING MAGHlNES.

(Application filed Mar. 31, 1902.) v (No IdQel.) 2 Sheets-Shet 2.

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ilwrrno STATES PATENT OFFICE.

EDW'ARD B. ALLEN, OF ELIZABETH, NEl/V JERSEY, ASSIGNOR TO THE SINGERMANUFACTURING COMPANY, A CORPORATION OF N EW' JERSEY.

THREAD-CONTROLUNG DEVICE FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent No. 713,584, dated November18, 1902.

Application filed March 31, 1902. Serial No. 100,760. (No model.)

To all whom it may concern:

Be it known that I, EDWARD B. ALLEN, a citizen of the United States,residing at Elizabeth, in the county of Union and State of New Jersey,have invented certain new and useful Improvements in Thread-ControllingDevices for Sewing-Machines, of which the following is a specification,reference being had therein to the accompanying drawings.

In many buttonhole-stitching machines now in use the stitclrformingmechanisms so operate that a loop of needle-thread (usually the threadof the depth-stitch needle) is engaged by a looper beneath thework-plate at the time when the machine is stopped at the completion ofa buttonhole, so that when the work is shifted for the purpose ofstitching the next buttonhole a doubled length or section ofneedle-thread will extend from one buttonhole to another on the lowerside of the work in addition to a single length orsection oflooper-thread, and when the needle thread or threads running between thebuttonholes on the upper side of the work are trimmed off loose ends orwhiskers are liable to or do appear on the under side of the work. Evenif the depth-stitch thread be cut by an automatic or otherthread-cutter, which severs the needle thread or threads close to theupper side of the work before the latter is shifted for a newbutton-hole, the thread comprised in the loop around the looper andequaling in length the distance from the work above the throat-platedown to and around the looper and back to the work will still remain asa loose end or whisker at each buttonhole, which is objectionable.

This invention has for its object to avoid the objection referred to byproviding means for preventing the needle-thread from forming a loop tobe engaged or entered by the looper at the time when the lasthalf-formed stitch of a buttonhole would otherwise be made, so thatthere will be no loop of needlethread beneath the work or beneath thethroat-plate when the machine is stopped and the work is shifted for thenext buttonhole, and thus no needle-thread will extend between thebuttonholes on the lower or inner side of the work. This object iseffected by providing an automatic mechanism which will place such extrastress on the needlethread as will take up all the slack thread betweenthe tension device and the eye of the needle after the last completestitch of a buttonhole hasbeen formedin suchamannerthat no loop can bethrown out by the needle to be entered by the looper at the moment themachine is to be stopped previously to shifting the work for the nextbuttonhole, and thus at the time the work is shifted there will be noloose needle-thread below the work and no needle-thread will extendbetween the buttonholes on the lower side of the completed work. Inother words, the invention provides an automatic loop-robbing device fora particularly-timed stitch or needle descent in the cycle of operationsnecessary for Working a buttonhole or group of stitches on an automaticmachine, the automatic loop-robbing device being preferably of suchconstruction as to serve also as a thread-slackening device to drawsufiicient needle-thread through the tension device to reach from onebuttonhole to the next above the work when the work is shifted.

In the accompanying drawings, Figure 1 is a side View of abuttonhole-stitching machine embodying the present invention. Fig. 2 isa detail plan view illustrative of the loop-robbing device, and Fig. 3 adetail side view of the same. Fig. 4 is a detail view looking from theright of Fig. 3, and Fig. 5 is a detail sectional side view illustratinglooping devices in connection with which the present invention may beemployed.

Referring to the drawings, Adenotes a base, rigid with which is awork-support A, said base being provided with a standard A with which amovable stitch-frame B has preferably a double pivotal connection, as inthe machine fully shown and described in my United States application,Serial No. 24,679, filed JulyQe, 1900. It will be understood, of course,that the present invention is not confined to any particularconstruction of automatic buttonhole or other sewing machine and thatits present illustration is merely intended to show one form of machinein connection with which it may be employed. The stitch-forming devicesof the machine herein shown comprise out-of-time depth-stitch and slitor edge needles d d and thread-carrying and nonthread-carryingloopersfandf all mounted for periodical rotary movements about the eyes of thebuttonholes, as in the machine shown in my application above referredto; but it will of course be understood that in utilizing the presentinvention in connection with a machine for working eyed buttonholeseither the work or the stitch-forming devices may be periodicallyrotated to stitch the eyes of the buttonholes, and it will also beunderstood that the invention is equally applicable to machines forworking straight buttonholes, eyelets, barring or staying or sewing onbuttons, or othermachines for formingseparated groups of stitches of anykind and employing stitch-forming mechanisms comprising loopers andforming chain-stitch (in contradistinction to lock-stitch) seams.

The present machine is shown as being provided with tension devices 0and O and takeup devices or arms D and D for the threads of the twoupper needles employed; butif the present invention were to be appliedon a machine having a lower slit needle the threadcontrolling devicesfor said lower needle would preferably be differently located than atthe top of the arm of stitch-frame, as here in shown. Placedconveniently adjacent to the tension device 0 and take-up device D forthe depth-stitch needle d is a lever E, having its fulcrum on the screwor stud e and preferably having a slotted lower arm engaged by a pin orlugf at the upper end ofalever F, controlled by a springf, whichnormally holds said lever F in the position shown in full lines in Fig.l.

P denotes the clutch-controlling or stopmotion lever of the machineembraced by my application hereinbefore referred to, and to which leveris attached the rear end of a rod 0", havinga lug or projection r to beengaged by a tripping lug or projection Q12 on the rotating cam-wheel g,which controls the rotating movements of the stitch-forming devices, theengagement of the said tripping lug or projection Q12 with the said lugor projection 9' serving to operate the clutch-controlling stop-motionleverP, so as to stop the machine at the completion of a buttonhole, andas the said lug or projection 'r is so arranged that its upper part willengage the lower end of the lever F said lever will be operated toactuate the leverE at the instant just before the machine is stopped.

The upper arm of the lever E is provided with a thread-controller,preferably in the form of a spring-wire looped arm e, arranged to act onthe thread between the tension device O and the needle and alsopreferably between the take-up arm or device D and the needle, althoughthis last-mentioned pointis notessential. Thespring thread-controllingarm e extends upward through a loop 6 on the upper arm of the lever Eand which loop 8 serves to limit the movements of the springarm erelative to the lever E in both directions.

The operation of the loop-robbing device is as follows: When the rod 1',controlling the stop-motion lever P, is shifted to the right, Fig. 1, tostop the machine at the completion of a buttonhole, the levers F and Eare moved from the positions shown in full lines to the positionsdenoted by dotted lines in Figs. 1 and 3, causing the springthread-controlling arm 6, connected with said lever E, to so act on thethread running to the depth-stitch needle cl as to take up all the slackof said thread and to put the said thread under such tension as will.prevent said needle at this time from throwing out a loop to be enteredby the non-thread-carryinglooper f so that said needle-thread will notat what would be the stitch next after the last stitch of a completedbuttonhole be detained beneath the throat-plate of the machine. Fromthis it results that when the work is shifted from a position forforming one buttonhole or one group of stitches to another there Will beno needle-thread on the lower side of the work between the separatedgroups of stitches, thereby not only obviating the present existingobjection to the presence of the useless and unsightly surplus threadwhere it is not wanted, but resulting in a considerable saving of therelatively costly silk needle-thread usually employed in stitchingbuttonholes.

The lever E, when operated, as above described, to take up all the slackthread between the tension device and the needle, is preferably given amovement of sufficient range or extent not only to take up all the slackreferred to, but also to draw through the tension device sufficientslack thread to extend from one buttonhole or separated group ofstitches to another on the upper side of the work, and thus obviates thenecessity for drawing or pulling out this requisite slack threadmanually or for providing a special slack-thread-drawing device for thispurpose, it being understood that the tension will be automaticallyreleased, as is usual, prior to the time when the extra slack referredto is drawn through the tension device. In performing its doublefunctions referred to the lever E is at one time given sufficientmovement to effect the results stated; but after having taken up all theslack thread the spring-arm e engaging the threads yields, owing to itspressure on the thread, and is under sufficient stress or tension, sothat as soon as the tension of this tension device is released thestress of the spring-arm e acts to draw through the said device theslack thread necessary to extend to the next buttonhole or group ofstitches by utilizing the stored-up power due to the stress or tensionunder which the said spring-arm is placed.

This invention is not to be understood as being limited to theparticular mechanism or l 4' H. I

the special means herein shown and described for preventing the looperfrom engaging or entering a loop of needle-thread at the needle descentor stroke occurring just next or after the completion of a group of apredetermined number of stitches, as this result may be accomplished inother ways than that hereinbefore described, as by automaticallythrowing either the needle or the looper slightly out of time with itsnormally cooperating complementary stitch-forming element at theparticular stroke of the needle referred to or by automatically movingthe looper sidewise slightly at the needle-stroke referred to, so as tocause said looper to avoid the needle-loop formed at that time.

Having thus described my invention, I claim and desire to secure byLetters Patent 1. In a sewing-machine for forming sepa rated groups ofstitches, the combination with a stitch-forming mechanism comprising aneedle and a cooperating looper, of automatic means for preventing theneedle-thread from being detained beneath the throat-plate at theneedle-stroke occurring next after the completion of a group ofstitches.

2. In a sewing-machine for forming separated groups of stitches, thecombination with a stitch-forming mechanism comprising a needle and acooperatinglooper, of an automatic loop-robbing device for preventingthe needle-thread from being detained beneath the throat-plate by thelooper at the end of the completion of a group of stitches.

3. In a sewing-machine for forming separated groups each comprisingapredetermined number of stitches, the combination with a needle and acooperating looper, of a stopmotion mechanism for controlling the numberof stitches for each group of stitches, and an automatic loop-robbingdevice operated from and controlled by said stop-motion mechanism.

4. In a sewing-machine for forming separated groups of stitches, thecombination with a stitch-forming mechanism comprising a needle and acooperating looper, of a slack-controlling and thread-drawing leverhaving a spring-arm or yielding resilient portion, and automatic meansfor causing said lever to take up the slack needle-thread at the end ofthe completion of a group of predetermined number of stitches, saidlever having a range of movement greater than is necessary to controlthe slack thread to be taken up so that said springarm or yieldingresilient portion of said thread-controllin g lever will be placed undertension, thereby storing up power in said arm or resilient portion to beutilized, without further movement of said arm, to draw slack threadfrom the tension device, when the normal tension on the thread isreleased.

5. In a sewing-machine for forming separated groups of stitches, thecombination with a stitch-forming mechanism comprising a needie and acooperating looper, of the needlethread-controlling lever E providedwith the spring-arm e, the stop-motion or clutch-controlling lever P andconnections between said levers E and P whereby the former will beoperated by the latter when the machine is stopped.

6. In a sewing-machine for forming separated groups of stitches, thecombination with astitch-forming mechanism comprising a needle and acooperating looper, of the needlethread-controlling lever E providedwith the spring-arm e, the stop-motion or clutch-controlling lever P,the rod or bar 1" provided with a lug or projection, and the lever Foperatively connected with the said lever E and arranged to be engagedby the said lug or projection of the rod or bar 0" to operate said leverE to cause it to take up the slack of the needle-thread when the machineis stopped.

In testimony whereof I affix my signature in presence of two witnesses.

EDWARD B. ALLEN.

Witnesses:

HENRY J. MILLER, HENRY A. KORNEMANN.

